comments

It sounds like you want to to add a large number of symbols to DSM at once. To add multiple new symbols, you’d need to Crtl/CMD+A on the symbols page (left sided column) to highlight all symbols and then you can sync them all in one go.

If you meant the opposite, that you wanted to import all DSM symbols into Sketch, this is not possible in one click; you would need to drag them out 1 by 1.